A conventional electronic cash register is provided with a mechanism for preventing a winding slack of a roll paper as disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2003-54790). The electronic cash register comprises a device body having a hollow structure that is open at its front and a drawer box open at its top is mounted in the device body so as to be slidable forward and backward. The device body comprises a ticket printer which is provided with a medium holding device for holding the roll paper.
When the drawer box is moved forward and backward, an impact thereof is exerted even on the medium holding device from the device body so that there occurs a case where the wound portion of the roll paper separates from a holding roller included in the medium holding device.
In such a case, slack may occur in the roll paper to cause a paper jam, but in the medium holding device, the wound portion of the roll paper separating from the holding roller falls down so that the wound portion automatically rotates in its winding direction to cancel the slack.
Accordingly, since the electronic cash register is not subjected to the occurrence of slack of the roll paper held by the medium holding device even if the drawer box is moved, the ticket can be well issued by the ticket printer.